Pat Johnson

Stem cells must maintain proliferation during tissue development, repair and homeostasis, yet avoid tumor formation. In Drosophila, neural stem cells (neuroblasts) maintain proliferation during embryonic and larval development and terminate cell cycle during metamorphosis. An important question for understanding how tissues are generated and maintained is: what regulates stem cell proliferation versus differentiation? We performed a genetic screen which identified nucleostemin 3 (ns3) as a gene required to maintain neuroblast proliferation. ns3 is evolutionarily conserved with yeast and human Lsg1, which encode putative GTPases and are essential for organism growth and viability. We found NS3 is cytoplasmic and it is required to retain the cell cycle repressor Prospero in neuroblast cytoplasm via a Ran-independent pathway. NS3 is also required for proper neuroblast cell polarity and asymmetric cell division. Structure-function analysis further shows that the GTP-binding domain and acidic domain are required for NS3 function in neuroblast proliferation. We conclude NS3 has novel roles in regulating neuroblast cell polarity and proliferation.

In August 2016 the National Oceanic and Atmospheric Administration released the National Water Model (NWM) expanding the nation's modeling scope from 9,000 to 2,700,000 reaches across the continental United States. In the same way the National Hydrography Dataset provides a nationally consistent geospatial database, the NWM offers the beginnings of a nationally consistent flow volume and velocity database. Unlike the NHD, which can be housed on modern hardware, the daily NWM output amounts to over 400 gigabytes posing challenges to data management, access and use.
In this paper we introduce an R package containing a historical archive of reach-based annual, seasonal, and monthly average daily flows for the NHD derived from a long-term retrospective run of the National Water Model. Included are functions for extracting NHD geometries, joining flow data, and writing the results to common GIS formats. These functionalities supplement the existing statistically derived annual flow volume estimates introduced in the NHDPlus (2006).
Further, we introduce a web application that lets user’s subset, visualize, and download information from the National Hydrography Dataset (NHD) merged with current to five day-out streamflow forecasts from the National Water Model. In doing so we offer an efficient (both in time and memory) methodology for joining the NHD to real-time NWM output and focus on visualizing this spatiotemporal database though an interactive interface that illustrates both current flow states as well as there reaction to historic patterns. The end goal is to explore how online cartographic methods can enrich the value of NWM data for the general public while offering capacities for improved place-based understanding, general water awareness, and NWM use. The application is in the public domain and can be accessed through a homepage at: mikejohnson51.github.io/FlowFinder